Depending on how much email you get everyday, it's quite possible that attaining Inbox Zero and maintaining it isn't feasible for you. It all comes down on how you use your email and what you can do to reduce the clutter and the noise so that you can get the job done.

I get about 20 to 50 emails a day and it took me months to whittle down my over-bloated inbox into Inbox Zero. The most difficult part wasn't archiving and indexing the emails, or the incoming flow of emails. It was actually addressing issues on which I had procrastinated. Anyway, I got through it and have maintained Inbox Zero since I attained it. I've had to seriously modify the way I use my email, but all in all, it's a welcome sight when at the end of the day, my inbox is completely empty.

If this isn't possible in your case, then you should try and prioritize emails thanks to indexing, virtual folders, and Gmail's Priority Inbox. Don't disregard the power of that new feature from Gmail. If used well, you can attain inbox zero for your priority inbox, which is better than nothing. All of the notifications and emails that you still want to keep in your inbox are still there instead of being archived.

If you can't use Gmail's Priority Inbox, then you can star, index, and label your emails manually. You can also create rules so that your inbox does this automatically. Then, you can try and ignore some of these emails while addressing more important ones. In a sense, you're creating your own priority inbox. We've found that it's just easier to use Gmail's service than to try and do so by yourself, but if you've got no choice, then you can try this.

There is no need to contact every single person that sends you an email, which is why you need to prioritize. In fact, I do something similar, but I just press archive or delete when I'm not interested in replying to some emails; not every single query needs an answer. Naturally, I do so for low-priority emails, not important stuff that absolutely needs to be addressed. It's all about finding some sort of balance.